This invention relates to a fitting that can be used with an underground glass fiber reinforced plastic storage tank. The fitting has a metal connector to which external plumbing connections can be made to allow fluid to be placed into or withdrawn from the underground storage tank. The metal fitting is substantially encased in glass fiber reinforced plastic so that the metal fitting is protected from the corrosive environment where underground storage tanks are normally located.
In past underground storage tanks metal pipes have been used to provide access to the interior of the tank. The metal pipe is positioned in a hole that passes through the inner and outer walls of the tank. The metal pipe is usually bonded to the walls of the tank to secure the pipe to the tank. In other applications the metal pipe pases through a reservoir which is formed on the exterior of the tank to contain leak detecting fluid. The metal pipe passes through an opening in the metal lid on the reservoir, extends through the reservoir and through the outer and inner walls of the tank to provide access to the interior of the tank. The metal pipe is secured to the inner wall of the tank and also welded or otherwise secured to the metal lid on the reservoir. In both applications the metal pipe extends above ground to provide access to the interior of the tank. In these applications the metal pipe is exposed to the corrosive environment in which the underground storage tank is positioned. This frequently results in leaks or corrosion damage to the metal pipe. In the tanks where a reservoir for leak detecting fluid is used leaks can occur at the joints between the metal lid of the reservoir and the metal pipe. Obviously, any type of leak can create a great deal of difficulty with an underground storage tank and limit the useful life of the tank. Underground storage tanks are made of glass fiber reinforced plastic to resist the corrosive environment of the ground where the tank is buried. By using metal piping and metal fittings to provide access to the interior of the tank, a serious corrosion problem still exists for the underground storage tanks.
Accordingly, it is desirable to have an improved fitting that provides access to a double wall underground storage tank that can effectively resist the corrosive environment where the tanks are located.
It is a further object of the invention to have a fitting to provide access to the interior of the tank that is encased in a non-corrosive glass fiber reinforced plastic material.
These other and other objects and advantages of the invention will be more readily understood by the following detailed description of the invention.